Method, system and apparatus for multi-terminal communication

ABSTRACT

A multi-terminal communication method, system and apparatus are provided. The method includes: receiving a call request originated by a caller to a voice terminal of a callee, where the call request carries a video media identifier; and setting up a voice session between the voice terminal of the callee and the caller and setting up a video session between a video terminal of the callee and the caller according to the video media identifier. With the present disclosure, a Service Broker Function server (SBF) sets up a voice session between the caller and the voice terminal of the callee and a video session between the caller and the video terminal of the callee so that it is unnecessary for data exchanged between the caller and the callee (multiple terminals) to pass through a local server. The burden of the local server is thereby relieved.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2008/073608, filed on Dec. 19, 2008, titled “Method, System andApparatus for Multi-Terminal Communication”, which claims priority ofChinese Patent Application No. 200710301347.X, filed with the ChinesePatent Office on Dec. 25, 2007 and entitled “Method, System andApparatus for Multi-Terminal Communication”. The contents of the aboveidentified applications are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present disclosure relates to mobile communication technologies, andin particular, to a method, system and apparatus for multi-terminalcommunication.

BACKGROUND OF THE INVENTION

Internet Protocol Television (IPTV) is a television and broadcastservice based on Internet Protocol (IP). With a TV set or personalcomputer as a display terminal, IPTV provides broadband servicesincluding digital broadcast and TV, video, information, interactivecommunity, interactive recreation and entertainment, and electroniccommerce over a broadband network. IPTV is characterized byinteractivity and real time. An IPTV system includes the streamingservice subsystem, program collecting and editing subsystem, storagesubsystem and authentication and accounting subsystem. The main contentsstored and delivered are streaming media files. The transport of IPTV isbased on an IP network. Generally, a local server is set at the networkedge and the user terminal may be an IP Set Top Box (STB) with a TV set,or a personal computer. The user terminal is also referred to as “UserEquipment (UE)” hereinafter. With the wide deployment and rapidpopularity of IPTV services, more and more IPTV based convergentservices will arise. For example, a user may bind his fixed line, mobilenumber or Personal Phone System (PHS) number with IPTV. When anotheruser capable of video communication attempts to make a video call to theuser while the fixed telephone set or mobile phone of the user does notsupport video communication, the user can display the video part of thecommunication via IPTV.

When implementing the present disclosure, the inventor finds that, inthe prior art, to engage multiple terminals in one communicationsession, a Session Transfer Server (STS) is required to communicate withthe peer on behalf of the multiple terminals. The voice data and videodata sent from the peer are first received by the STS. Then the STSdecodes the voice data and video data and sends them to multipleterminals individually. Likewise, the STS needs to combine data sent bythe multiple terminals and send the data to the peer. As a result, thelocal server where the STS operates is heavily loaded and a lot of localserver resources are consumed. The system performance is therebyhindered.

SUMMARY OF THE INVENTION

Embodiments of the disclosure intend to provide a multi-terminalcommunication method, system and apparatus so as to resolve the issue inthe prior art that the STS of the local server must be engaged tocommunicate with the peer on behalf of multiple terminals, which causesa heavy burden to the local server and consumes a lot of resources ofthe local server.

The objectives may be achieved through the following solutions. Amulti-terminal communication method includes: receiving a call requestoriginated by a caller to a voice terminal of a callee, where the callrequest carries a video media identifier; and setting up a voice sessionbetween the voice terminal of the callee and the caller and setting up avideo session between a video terminal of the callee and the calleraccording to the video media identifier. A multi-terminal communicationsystem comprises a caller and a Service Broker Function server (SBF).The caller is adapted to originate a call request to a voice terminal ofa callee via the SBF, where the call request carries a video mediaidentifier The SBF is adapted to set up a voice session between thevoice terminal of the callee and the caller and set up a video sessionbetween a video terminal of the callee and the caller according to thevideo media identifier.

A Service Broker Function server (SBF) comprises a request receivingmodule, a voice session setup module and a video session setup module.The request receiving module is adapted to receive a call requestoriginated by a caller to a voice terminal of a callee, where the callrequest carries a video media identifier. The voice session setup moduleis adapted to set up a voice session between the voice terminal of thecallee and the caller The video session setup module is adapted to setup a video session between a video terminal of the callee and the calleraccording to the video media identifier received by the requestreceiving module.

The solutions of the embodiments of the disclosure provide the followingbenefits: because the SBF sets up a voice session between the caller andthe voice terminal of the callee and a video session between the callerand the video terminal of the callee, it is unnecessary for dataexchanged between the caller and the callee (multiple terminals) to passthrough a local server. This relieves the burden of the local server. Inaddition, the embodiments of the disclosure only require additionalsignaling exchange between the SBF and the caller/callee. No extraburden is imposed on the SBF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a signaling flow of a multi-terminal communication methodaccording to a first embodiment of the disclosure;

FIG. 2 is a signaling flow of UE registration in a multi-terminalcommunication method according to a second embodiment of the disclosure;

FIG. 3 is a signaling flow where the video terminal STB of the calleesubscribes with the SBF to the session status of the bound voiceterminal of the callee in a multi-terminal communication methodaccording to the second embodiment of the disclosure;

FIG. 4 is a signaling flow of IPTV based multi-terminal communication ina multi-terminal communication method according to the second embodimentof the disclosure;

FIG. 5 is a signaling flow of IPTV based multi-terminal communication ina multi-terminal communication method according to a third embodiment ofthe disclosure; and

FIG. 6 is a schematic drawing showing a structure of a multi-terminalcommunication system according to an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure is hereinafter described in detail with referenceto the accompanying drawings and preferred embodiments.

First Method Embodiment

FIG. 1 shows the procedure of a computer-implemented method formulti-terminal communication according to the first embodiment of thedisclosure. The method according to the first embodiment includes thefollowing steps:

Step 101: Receive a call request originated by a caller to a voiceterminal of a callee, where the call request carries a video mediaidentifier.

Step 102: Set up a voice session between the voice terminal of thecallee and the caller and set up a video session between a videoterminal of the callee and the caller according to the video mediaidentifier.

In the first embodiment, a Service Broker Function server (SBF) isadopted to set up sessions between the caller and multiple terminals ofthe callee respectively. Suppose the callee has an STB and a mobilephone. Then the SBF sets up a video session between the STB and thecaller and sets up a voice session between the mobile phone and thecaller. Therefore, it is unnecessary for data exchanged between thecaller and the callee (multiple terminals) to pass through the localserver and thus the burden of the local server is relieved. In addition,according to the first embodiment, it is only necessary to add signalinginteractions between the SBF and the caller/callee. No extra burden isimposed on the SBF.

Second Method Embodiment

To better explain the technical solution proposed by the firstembodiment of the multi-terminal communication method, the secondembodiment presents a life scenario, where the multiple terminals of thecallee are an STB and a fixed telephone set. The scenario is presentedto help explain the technical solution of the first embodiment of themulti-terminal communication method and not intended to limit theapplication of the method to only such a scenario.

Suppose the STB and fixed telephone set of user A are bound and the STBsubscribes to the session status of the fixed telephone set which doesnot support video reception and display. When user B originates a videocall request to the fixed telephone set of user A, user A answers thecall and simultaneously, the TV screen displays video data coming fromuser B and asks whether to receive the video. User A chooses to receivethe video and then talks with user B via the fixed telephone set andviews the video from user B on the TV screen. If the TV set of user A isnot on when user B sends a call request to the fixed telephone set ofuser A, user A answers the call and user B tells user A that user B cansend video data. Then user A can turn on the TV set when an inquiry popsup on the TV screen, asking whether to receive the video of user B. UserA chooses to receive the video and then talks with user B via the fixedtelephone set while watching the video from user B on the TV screen.

In an IPTV system based on an IP Multimedia Subsystem (IMS), a voiceterminal may be an STB, a mobile phone or a fixed telephone set; an IPTVService Control Function (IPTV SCF) is adapted to manage IPTV relatedservices; the SBF is a key network element of convergent services andworks as a common interface between various services such as IPTV andvoice services. An IPTV Media Function includes a Media Control part anda Media Delivery part, adapted to control and deliver media data.

In the second embodiment of the multi-terminal communication method, theprecondition is that the UE registers successfully with the SBF and aGeneral Telecommunication Application Server (GTAS). The GTAS isequivalent to a call control/processing server in a telephone system andfunctions to control signaling exchanged between the caller and thecallee, such as ringing, off-hook and on-hook signaling. According tothe second embodiment of the multi-terminal communication method, a UEregistration procedure is proposed.

FIG. 2 is a signaling flow of UE registration according to the secondembodiment of the multi-terminal communication method in the presentdisclosure. The procedure includes the following steps:

Step S401: The UE sends a REGISTER request to the IMS core layer.

Step S402: The IMS core layer returns a SIP 401 message to the UE. TheSIP 401 message is returned via a server to a client, indicating theclient is not authorized. (When the UE sends the first request, a SIP401 message returned means the UE is not authorized. In this case, theUE needs to send another REGISTER request, carrying authenticationinformation of the UE, such as the user name and password. It is arequirement of the Session Initiation Protocol (SIP) for the UE to sendtwo REGISTER requests).

Step S403: The UE sends another REGISTER request to the IMS core layer.

Step S404: The IMS core layer returns a 200 OK to the UE.

Step S405: A third-party registration according to the Initial FilterCriteria (IFC) is initiated. IFC is a part of subscription data storedin a Home Subscriber Server (HSS) and downloaded to the Serving CallSession Control Function (S-CSCF) allocated for the UE when the UE isregistered. IFC defines service trigger conditions and destinationApplication Servers (ASs) according to different priorities. The S-CSCFperforms IFC matching when processing a service request from the UE andif the trigger condition is met, triggers the specified AS so that theAS can control the service according to a service logic defined in theAS. Third-party registration refers to a registration automaticallyinitiated by the S-CSCF for the UE according to the IFC of the UE. Thismeans the UE only registers with the IMS core layer but the IMS corelayer detects that the UE must also register with a server according tothe IFC of the UE and helps the UE to register automatically.

Step S406: The IMS core layer sends a REGISTER request to the SBF onbehalf of the UE.

Step S407: The SBF returns a 200 OK to the IMS core layer, indicatingthe UE is registered successfully.

Step S408: The IMS core layer sends a REGISTER request to the GTAS onbehalf of the UE.

Step S409: The GTAS returns a 200 OK to the IMS core layer, indicatingthe UE is registered successfully.

For easy description, terminals of the callee include an STB andtelephone sets. It is necessary to set a binding between the videoterminal STB of the callee and the voice terminal (such as a fixedtelephone set, a PHS terminal or a mobile phone) and the video terminalSTB of the callee must be able to know the session status of the boundvoice terminal of the callee. Therefore, the video terminal STB of thecallee must send a SUBSCRIBE request to the SBF, requesting the SBF ofthe callee to notify the video terminal STB of the call request when theSBF receives a call destined for the voice terminal of the callee boundwith the STB.

FIG. 3 is a signaling flow where the video terminal STB of the calleesubscribes with the SBF to the session status of the voice terminal ofthe callee bound with the STB in the second embodiment of thedisclosure. In FIG. 3, the STB of the callee is successfully registeredwith the IPTV SCF.

Step S501: The video terminal STB of the callee sends a SUBSCRIBErequest to the SBF via a SUBSCRIBE command which carries informationabout the voice terminal bound with the STB.

Step S502: The SBF checks whether the voice terminal of the callee isbound with the video terminal STB of the callee according to the voiceterminal information carried in the SUBSCRIBE request and if they arebound, the SBF decides to accept the SUBSCRIBE request of the STB of thecallee and executes step S503; otherwise, the SBF rejects the SUBSCRIBErequest of the STB of the callee.

Step S504: The SBF returns a subscription success message to the STB ofthe callee via a NOTIFY command. After successful subscription of theSTB of the callee, if a caller sends a call request to the voiceterminal of the callee bound with the STB of the callee, the SBF alsoforwards the call request to the STB of the callee.

Fourth Method Embodiment

FIG. 4 is a signaling flow of a multi-terminal communication methodbased on IPTV in the second embodiment of the disclosure. In FIG. 4, thevideo terminal STB of the callee has already successfully subscribedwith the SBF to the session status of the voice terminal of the calleebound with the STB. In the embodiment, the callee includes at least onevoice terminal (such as a fixed telephone set, a PHS terminal and amobile phone) and one video terminal (such as an STB). The procedureincludes the following steps:

Step S601: A caller sends an INVITE message to the SBF, where theSession Description Protocol (SDP) 1 information in the INVITE messagecarries a video media identifier indicating that the caller isrequesting an audio and video session. The SDP1 information alsoincludes capability information of the caller, such as whether thecaller supports the video session.

Step S602: Upon reception of the INVITE message from the caller, the SBFchecks whether the SDP 1 of the INVITE message carries a video mediaidentifier and if so, the SBF records the video session request. The SBFalso judges whether the caller supports the video session according tothe capability information of the caller in the SDP1 information and ifthe caller does not support the video session, the SBF will not set upthe video session for the caller even though the SDP 1 sent by thecaller carries a video media identifier.

Step S603: The SBF forwards the INVITE message to the voice terminal ofthe callee.

Step S604: The voice terminal of the callee answers the call and returnsto the SBF a 200 OK which carries SDP2 information of the voice terminalof the callee. The SDP2 information also carries capability informationof the voice terminal.

Step S605: The SBF decides whether the voice terminal of the calleesupports video communication according to the SDP2 information of thevoice terminal of the callee carried in the 200 OK response. If thevoice terminal of the callee does not support video communication, theSBF forwards the response of the voice terminal of the callee to thecaller and sets up a voice session between the caller and the voiceterminal of the callee after the caller receives the response.

Step S606: The SBF searches for the video terminal of the callee boundwith the voice terminal of the callee according to the video sessionrequest recorded in step S602 and notifies the video terminal of thecallee to initiate a video session request according to the INVITEmessage sent by the caller to the voice terminal of the callee.Specifically, a NOTIFY message (for example, Notify<Request-URI:STB>Body:state=confirmed;call-id;fromtag;totag) may be sentto notify the video terminal of the callee to initiate the video sessionrequest.

Step S607: Upon reception of the NOTIFY message from the SBF, the videoterminal of the callee displays the video session request on theterminal screen, asking whether the callee agrees to connect the videoof the caller. Preferably, a timer is started when a session request isreceived from the caller. When the timer expires but an instruction ofuser agreement is not received, the video session request is rejected bydefault. If the callee does not agree to accept the video sessionrequest, the video terminal of the callee does not send a video sessionjoin request.

Step S608: If the callee agrees to accept the video session request, thevideo terminal of the callee sends a video session join request to theSBF. Specifically, the video terminal of the callee sends a videosession INVITE message to the SBF and writes a Join header carried inthe INVITE message, such as Join:xxx;to-tag=xxx;from-tag=xxx, whichnotifies the SBF that the video terminal wishes to join an existingsession. The INVITE message also carries SDP information (SDP3) of thevideo terminal of the callee. The SDP3 includes video descriptioninformation of the video terminal of the callee.

Step S609: Upon reception of the video session INVITE message from thevideo terminal of the callee, the SBF matches the voice session alreadyexisting between the caller and the voice terminal of the calleeaccording to the Join header carried in the INVITE message and combinesthe video capability of the video terminal of the callee and the voicecapability of the voice terminal. Afterwards, the SBF sends a REINVITEmessage to the caller, requesting the caller to set up a video session.Specifically, the SBF adds the video description information of SDP3 toSDP2 to generate new SDP information, SDP4, and sends the REINVITEmessage carrying SDP4 to the caller. Thus the caller knows that the peerrequesting a video session is the callee with which a voice session isalready established.

Step S610: The caller receives the REINVITE and returns to the SBF a 200OK where the SDP information (SDP5) carries video descriptioninformation and voice description information of the caller.

Step S611: The SBF receives the 200 OK response from the caller andremoves the voice description information of the caller carried in theSDP5 and sends the new SDP5 without the voice description information ofthe caller to the video terminal of the callee via a 200 OK. If the SBFdoes not remove the voice description information of the caller, a voicesession between the caller and the video terminal of the callee will beset up in addition to the video session between the caller and the videoterminal of the callee.

Step S612: The video terminal of the callee receives the INVITE messagefrom the SBF and returns an ACK message.

Step S613: The SBF forwards the ACK from the video terminal of thecallee to the caller so as to set up a video session between the callerand the video terminal of the callee. In the foregoing embodiment, thevideo terminal of the callee sets up a video session with the callerunder the control of the SBF so that the voice terminal of the calleethat does not support video reception is able to transfer the videosession with the caller to the video terminal of the callee bound withthe voice terminal of the callee. The SBF only needs to set up the videosession between the caller and the video terminal of the callee. This isunlike the prior art, where the SBF has to communicate with the calleron behalf of the multiple terminals of the callee. Therefore, the methodaccording to the embodiment of the disclosure does not add to the burdenof the SBF but effectively enables communication between multipleterminals and the caller.

FIG. 5 is a signaling flow of an IPTV based multi-terminal communicationmethod according to the third embodiment of the disclosure. As shown inFIG. 5, when the caller originates a session request, the video terminalof the callee is not online. The SBF sends an indication to the voiceterminal of the callee, instructing the callee to turn on the videoterminal of the callee. After the video terminal of the callee is turnedon, the video terminal sends a SUBSCRIBE request to the SBF to subscribeto the session status of the voice terminal of the callee. After thesubscription is successful, the SBF sets up a video session between thecaller and the video terminal of the callee so as to transfer the videosession with the caller to the video terminal of the callee bound withthe voice terminal of the callee.

Step S701: The caller sends an INVITE message to the SBF. The SDP1information of the INVITE message carries a video media identifier,indicating that the caller is requesting an audio and video sessioninstead of only an audio session. The SDP1 information also includescapability information of the caller, such as whether the callersupports the video session.

Step S702: Upon reception of the INVITE message from the caller, the SBFchecks whether the SDP1 of the INVITE message carries a video mediaidentifier and if so, the SBF records the video session request. The SBFalso judges whether the caller supports the video session according tothe capability information of the caller in the SDP1 information and ifthe caller does not support the video session, the SBF will not set upthe video session for the caller even though the SDP1 sent by the callercarries a video media identifier.

Step S703: The SBF forwards the INVITE message to the voice terminal ofthe callee.

Step S704: The voice terminal of the callee answers the call and returnsto the SBF a 200 OK which carries SDP2 information of the voice terminalof the callee. The SDP2 information also carries capability informationof the voice terminal of the callee.

Step S705: The SBF decides whether the voice terminal of the calleesupports video communication according to the SDP2 information of thevoice terminal of the callee carried in the 200 OK response. If thevoice terminal of the callee does not support video communication, theSBF forwards the response of the voice terminal of the callee to thecaller and sets up a voice session between the caller and the voiceterminal of the callee after the caller receives the response.

Step S706: The SBF searches for the video terminal of the callee boundwith the voice terminal of the callee according to the video sessionrequest recorded in step S702 and checks whether the video terminal ofthe callee is on. In this embodiment of the disclosure, the videoterminal is off and therefore the SBF instructs the callee to turn onthe video terminal via the voice terminal of the callee.

Step S707: The callee hears the indication of the SBF and turns on thevideo terminal of the callee if agreeing to accept the video request ofthe caller. After the video terminal of the callee is turned on, thevideo terminal must first successfully register with the IPTV SCF.

Step S708: After the video terminal of the callee is successfullyregistered, the video terminal sends a SUBSCRIBE request to the SBF,requesting to subscribe to the session status of the bound voiceterminal of the callee.

Step S709: The SBF receives the SUBSCRIBE request from the videoterminal of the callee and checks whether the video terminal of thecallee is bound with the voice terminal of the callee. If they arebound, the SBF allows the video terminal of the callee to subscribe tothe session status of the voice terminal of the callee. The SBF alsonotifies the video terminal of the callee to initiate a video sessionrequest. Specifically, a NOTIFY message (for example, Notify<Request-URI: STB>Body: state=confirmed;call-id;fromtag;totag) may besent to notify the video terminal of the callee to initiate the videosession request.

Step S710: Upon reception of the NOTIFY message from the SBF, the videoterminal of the callee displays the video session request on theterminal screen, asking whether the callee agrees to connect the videoof the caller. Preferably, a timer is started when a session request isreceived from the caller. When the timer expires but an instruction ofuser agreement is not received, the video session request is rejected bydefault. If the callee does not agree to accept the video sessionrequest, the video terminal of the callee does not send a video sessionjoin request.

Step S711: If the callee agrees to accept the video session request, thevideo terminal of the callee sends a video session join request to theSBF. Specifically, the video terminal of the callee sends a videosession INVITE message to the SBF and writes a Join header, such asJoin:xxx;to-tag=xxx;from-tag=xxx, which notifies the SBF that the videoterminal wishes to join an existing session. The INVITE message alsocarries SDP information (SDP3) of the video terminal of the callee. TheSDP3 includes video description information of the video terminal of thecallee.

Step S712: Upon reception of the video session INVITE message from thevideo terminal of the callee, the SBF matches the voice session alreadyexisting between the caller and the voice terminal of the calleeaccording to the Join header carried in the INVITE message and combinesthe video capability of the video terminal of the callee and the voicecapability of the voice terminal. Afterwards, the SBF sends a REINVITEmessage to the caller, requesting the caller to set up a video session.Specifically, the SBF adds the video description information of SDP3 toSDP2 to generate new SDP information, SDP4, and sends the REINVITEmessage carrying SDP4 to the caller. Thus the caller knows that the peerrequesting a video session is the callee with which a voice session isalready established.

Step S713: The caller receives the REINVITE and returns to the SBF a 200OK where the SDP information (SDP5) carries video descriptioninformation and voice description information of the caller.

Step S714: The SBF receives the 200 OK response from the caller andremoves the voice description information of the caller carried in theSDP5 and sends the new SDP5 without the voice description information ofthe caller to the video terminal of the callee via a 200 OK. If the SBFdoes not remove the voice description information of the caller, a voicesession between the caller and the video terminal of the callee will beset up in addition to the video session between the caller and the videoterminal of the callee.

Step S715: The video terminal of the callee receives the INVITE messagefrom the SBF and returns an ACK message.

Step S716: The SBF forwards the ACK from the video terminal of thecallee to the caller so as to set up a video session between the callerand the video terminal of the callee.

FIG. 6 is a schematic drawing showing the structure of a multi-terminalcommunication system based on IPTV according to an embodiment of thedisclosure. The system includes a caller 1 and an SBF 3. The caller 1originates a call request to a voice terminal 21 of a callee via theSBF3. The call request carries a video media identifier. The SBF 3 isadapted to: set up a voice session between the voice terminal 21 of thecallee and the caller 1, notify a video terminal 22 of the callee toinitiate a video session request according to the video mediaidentifier, and set up a video session between the video terminal 22 ofthe callee and the caller 1.

The SBF 3 includes a request receiving module 31, a voice session setupmodule 32, a notifying module 33 and a video session setup module 34.The request receiving module 31 is adapted to receive the call requestoriginated by the caller 1 to the voice terminal 21 of the callee, wherethe call request carries a video media identifier; the voice sessionsetup module 32 is adapted to set up a voice session between the voiceterminal 21 of the callee and the caller 1; the notifying module 33 isadapted to notify the video terminal 22 of the callee to initiate avideo session request to the caller according to the video mediaidentifier carried in the call request; the video session setup module34 is adapted to set up a video session between the video terminal 22 ofthe callee and the caller 1. The SBF 3 further includes a subscriberequest receiving module 35, a binding checking module 36 and asubscribe responding module 37. The subscribe request receiving module35 is adapted to receive a SUBSCRIBE request initiated by the videoterminal 22 of the callee, where the SUBSCRIBE request carries anidentifier of the voice terminal 21 of the callee requested by the videoterminal 22 of the callee; the binding checking module 36 is adapted tocheck whether the voice terminal 21 of the callee is bound with thevideo terminal 22 of the callee according to the identifier of the voiceterminal 21 of the callee; the subscribe responding module 37 is adaptedto return a subscription success response to the video terminal 22 ofthe callee after the binding checking module 36 determines that thevoice terminal 21 of the callee is bound with the video terminal 22 ofthe callee.

The SBF 3 may further include a join request receiving module 38, amatching and combining module 39 and a removing module 40. The joinrequest receiving module 38 is adapted to receive a video session joinrequest sent by the video terminal 22 of the callee, which requests tojoin the voice session between the voice terminal 21 of the callee andthe caller 1 and carries video capability description information of thevideo terminal 22 of the callee; the matching and combining module 39 isadapted to: match the video terminal 22 of the callee to the voicesession between the caller 1 and the voice terminal 21 of the calleeaccording to the video session join request, combine the videocapability description information of the video terminal 22 of thecallee with the voice capability description information of the voiceterminal 21 of the callee, and send a REINVITE message to the caller 1;the removing module 40 is adapted to remove the voice part from a 200 OKmessage upon reception of the 200 OK message and set up a video sessionbetween the video terminal 22 of the callee and the caller 1.

The SBF 3 may further include a judging module 41 and a turn-onindicating module 42. The judging module is adapted to judge whether thevideo terminal 22 of the callee bound with the voice terminal 21 of thecallee is online after the request receiving module 31 receives the callrequest originated by the caller to the voice terminal 21 of the callee,where the call request carries a video media identifier; the turn-onindicating module 42 is adapted to send an indication to the voiceterminal 21 of the callee when the judging module 41 determines that thevideo terminal 22 of the callee is not online, instructing the callee toturn on the video terminal 22 of the callee.

In this embodiment of the disclosure, the SBF can set up a voice sessionbetween the caller and the voice terminal of the callee and a videosession between the caller and the video terminal of the callee so thatit is unnecessary for data exchanged between the caller and the callee(multiple terminals) to pass through a local server. This relieves theburden of the local server. In addition, this embodiment of thedisclosure only requires additional signaling exchange between the SBFand the caller/callee. No extra burden is imposed on the SBF.

According to the preceding descriptions, those skilled in the art mayunderstand that embodiments of the present disclosure can be implementedby software on a necessary hardware platform or by hardware only. Inmost cases, the former is preferred. Based on such understanding, theessence of the technical solution of the present disclosure, orcontributions to the prior art by the solution may be represented by asoftware product, which may be stored in a computer-readable storagemedium, such as a Read-Only Memory/Random Access Memory (ROM/RAM), amagnetic disk, and a compact disk. The software product includes anumber of instructions that enable a computer device (which may be apersonal computer, a server or a network device) to execute the methodaccording to the embodiments of the disclosure.

Although the disclosure has been described through preferredembodiments, the disclosure is not limited to such embodiments. It isapparent that those skilled in the art can make various modificationsand variations to the disclosure without departing from the spirit andscope of the disclosure. The disclosure is intended to cover themodifications and variations provided that they fall in the scope ofprotection defined by the claims or their equivalents.

1. A multi-terminal communication method, comprising: receiving a callrequest originated by a caller to a voice terminal of a callee, whereinthe call request carries a video media identifier; and setting up avoice session between the voice terminal of the callee and the caller,and, setting up a video session between a video terminal of the calleeand the caller according to the video media identifier.
 2. The method ofclaim 1, further comprising: before the step of setting up the videosession between the video terminal of the callee and the calleraccording to the video media identifier, providing the video terminal ofthe callee with session status of the voice terminal of the callee. 3.The method of claim 1, further comprising: before the step of setting upthe video session between the video terminal of the callee and thecaller according to the video media identifier, notifying the videoterminal of the callee to initiate a video session request to the calleraccording to the video media identifier.
 4. The method of claim 2,further comprising: before the step of providing the video terminal ofthe callee with the session status of the voice terminal of the callee,receiving a SUBSCRIBE request initiated by the video terminal of thecallee, wherein the SUBSCRIBE request carries an identifier of the voiceterminal of the callee requested by the video terminal of the callee;and checking whether the voice terminal of the callee is bound with thevideo terminal of the callee according to the identifier of the voiceterminal of the callee and returning a subscription success message tothe video terminal of the callee after deciding that the voice terminalof the callee is bound with the video terminal of the callee.
 5. Themethod of claim 4, wherein the step of receiving the SUBSCRIBE requestinitiated by the video terminal of the callee comprises: receiving theSUBSCRIBE request initiated by the video terminal of the callee via aSUBSCRIBE command; and wherein the step of returning a subscriptionsuccess message to the video terminal of the callee comprises: returningthe subscription success message to the video terminal of the callee viaa NOTIFY command.
 6. The method of claim 1, further comprising:registering the voice terminal of the callee.
 7. The method of claim 1,wherein the step of setting up the video session between the videoterminal of the callee and the caller according to the video mediaidentifier comprises: receiving from the video terminal of the callee arequest to join the video session and deciding that the video terminalof the callee requests to join the voice session between the voiceterminal of the callee and the caller according to the request, whereinthe request carries video capability description information of thevideo terminal of the callee; matching the video terminal of the calleeto the voice session between the caller and the voice terminal of thecallee according to the request, combining the video capabilitydescription information of the video terminal of the callee with voicecapability description information of the voice terminal of the callee,and sending a REINVITE request to the caller; and removing voicecapability description information from a 200 OK upon reception of the200 OK from the caller and setting up the video session between thevideo terminal of the callee and the caller.
 8. The method of claim 7,wherein the step of deciding that the video terminal of the calleerequests to join the voice session between the voice terminal of thecallee and the caller according to the request comprises: deciding thatthe video terminal of the callee requests to join the voice sessionbetween the voice terminal of the callee and the caller according to aJoin header written by the video terminal of the callee and carried inthe request.
 9. The method of claim 7, wherein the video capabilitydescription of the video terminal of the callee comprises videoreception capability information of the video terminal of the callee, orvideo reception capability information of the video terminal of thecallee and video transmission capability information of the videoterminal of the callee.
 10. The method of claim 1, further comprising:before the step of setting up the video session between the videoterminal of the callee and the caller according to the video mediaidentifier, deciding that the video terminal of the callee is not onlineand sending an indication to the voice terminal of the callee toinstruct the callee to turn on the video terminal of the callee.
 11. Themethod of claim 10, further comprising: after the step of sending theindication to the voice terminal of the callee to indicate the callee toturn on the video terminal of the callee, providing the video terminalof the callee with session status of the voice terminal of the calleeafter the video terminal of the callee is turned on.
 12. Amulti-terminal communication system, comprising a caller and a ServiceBroker Function server (SBF), wherein the caller is adapted to originatea call request to a voice terminal of a callee via the SBF, wherein thecall request carries a video media identifier; and wherein the SBF isadapted to set up a voice session between the voice terminal of thecallee and the caller and set up a video session between a videoterminal of the callee and the caller according to the video mediaidentifier.
 13. A Service Broker Function server (SBF), comprising arequest receiving module, a voice session setup module, and a videosession setup module, wherein the request receiving module is adapted toreceive a call request originated by a caller to a voice terminal of acallee, wherein the call request carries a video media identifier;wherein the voice session setup module is adapted to set up a voicesession between the voice terminal of the callee and the caller; andwherein the video session setup module is adapted to set up a videosession between a video terminal of the callee and the caller accordingto the video media identifier received by the request receiving module.14. The SBF of claim 13, further comprising a notifying module, adaptedto notify the video terminal of the callee to initiate a video sessionrequest to the caller according to the video media identifier carried inthe call request received by the request receiving module.
 15. The SBFof claim 13, further comprising a subscribe request receiving module, abinding checking module and a subscribe responding module, wherein thesubscribe request receiving module is adapted to receive a SUBSCRIBErequest initiated by the video terminal of the callee, wherein theSUBSCRIBE request carries an identifier of the voice terminal of thecallee requested by the video terminal of the callee; wherein thebinding checking module is adapted to check whether the voice terminalof the callee is bound with the video terminal of the callee accordingto the identifier of the voice terminal of the callee; and wherein thesubscribe responding module is adapted to return a subscription successmessage to the video terminal of the callee after the binding checkingmodule decides that the voice terminal of the callee is bound with thevideo terminal of the callee.
 16. The SBF of claim 13, furthercomprising a join request receiving module, a matching and combiningmodule and a removing module, wherein the join request receiving moduleis adapted to receive from the video terminal of the callee a videosession join request which requests to join the voice session betweenthe voice terminal of the callee and the caller and carries videocapability description information of the video terminal of the callee;wherein the matching and combining module is adapted to: match the videoterminal of the callee to the voice session between the caller and thevoice terminal of the callee according to the video session joinrequest, combine the video capability description information of thevideo terminal of the callee with voice capability descriptioninformation of the voice terminal of the callee, and send a REINVITErequest to the caller; and wherein the removing module is adapted toremove voice capability description information from a 200 OK uponreception of the 200 OK from the caller and to set up the video sessionbetween the video terminal of the callee and the caller.
 17. The SBF ofclaim 13, further comprising a judging module and a turn-on indicatingmodule, wherein the judging module is adapted to judge whether the videoterminal of the callee is online; and wherein the turn-on indicatingmodule is adapted to send an indication message to the voice terminal ofthe callee when the judging module decides that the video terminal ofthe callee is not online, the indication message instructing the calleeto turn on the video terminal of the callee.